Great Extinctions

What are extinctions?

Permanent loss of a species

What are the types of extinctions?

Background

Mass

What are the types of Mass Extinctions

Timing

Multiple Ecosystems

Numbers

How many mass extinctions had Earth had?

Five

Extinction is a _____ part of Earth’s history

natural

What is the normal rate for extinction

1 species per 10,000 species per 100 years

What is the current rate of extinction

10-100 species per year

How hard an extinction hits a group depends on the _____ of extinction

mode

What is a background extinction

normal, ongoing loss of species over geological time

What is a mass extinction

widespread, rapid loss of biodiversity

How can you track a mass extinction

Fossil records

Identification of extinction causes

Fossil records are usually across ____ (geological boundaries)

strata

What are the “major players” of mass extinctions

Large-scale Volcanism

Asteroid Impacts

Climate Change

Ocean Anoxia

A large scale volcano can release

greenhouse gases and other compounds

What are the major things a large scale volcano can cause

rapid warming or cooling

acid rain

ocean acidification

What can an asteroid impact cause?

shockwaves

fire

dust

aerosols

rapid cooling

food-web collapse

Climate change alters habitats ____ than many species can adapt

faster

What can ocean anoxia cause

decreased oxygen content

What is a niche vacancies

survivors may occupy habitats left empty

What happens after a mass extinction

Niche Vacancies

Adaptive Radiation

Recovery Period

What is adaptive radiation

surviving lineages diversify into multiple new species

What is a recovery period

long term recovery to approach previous levels of diversity and primary productivity

What are the Big 5 Mass Extinctions

End-Ordovician

Late Devonian

End-Permian

End-Triassic

End-Cretaceous

How long ago did the End-Ordovician Mass Extinction occur

444 mya

What was the result of the End-Ordovician Mass Extinction

loss of majority of marine organisms

What caused the End-Ordovician Mass Extinction

Rapid global cooling

What followed the End-Ordovician Mass Extinction

Rapid warming

During the End-Ordovician Mass Extinction, what happened due to the rapid global cooling

formation of massive ice sheets

sea levels dropped

How long ago did the Late Devonian mass extinction occur

359 - 372 mya

What was the result of the Late Devonian mass extinction

75% of species were lost

What type of species were mainly impacted by the Late Devonian mass extinction

Marine Life

Armored Fish

What caused the Late Devonian mass extinction

expansion of land plants increased runoff

reduction in ocean oxygen

expansion of land plants

potential volcanism

During the Late Devonian mass extinction there was the expansion of land plants, what did this increase

chemical weathering

nutrients in waterways

algae content

How long ago did the end-permian mass extinction occur

252 mya

How long did the end-permian mass extinction last

50,000 years

What was the end-permian mass extinction called

The Great Dying

How much marine life went extinct due to the end-permian mass extinction

96%

How much terrestrial life went extinct due to the end-permian mass extinction

70%

How many families went extinct due to the end-permian mass extinction

50%

What were the effects/causes of the end-permian mass extinction

huge lava flow from Russia

toxic atmosphere

loss of ozone layer

global warming

acid rain

ocena acidification

mega hurricanes

During the end-permian mass extinction there were huge lava flows from Russia, this caused massive amounts of ______ to be released

Carbon Dioxide

What caused the toxic atmosphere during the end-permian mass extinction

Carbon dioxide and volcanic gas

How long ago did the End-Triassic mass extinction occur

201 mya

How much of the worlds population went extinct during the End-Triassic mass extinction

75%

What species were mainly impacted by the End-Triassic mass extinction

Large amphibians

Marine reptiles

During the End-Triassic mass extinction, what was released from Pangea splitting

Carbon Dioxide

What was the main cause of the End-Triassic mass extinction

global warming

How long ago did the end-cretaceous mass extinction occur

66 mya

How much of the earths population was killed off from the end-cretaceous mass extinction

75%

What were killed off during the end-cretaceous mass extinction

non-avian dinosaurs

plesiosaurs

marine plankton

marine reptiles

non-seed plants

Who survived the end-cretaceous mass extinction

deep sea organisms

What were the theories behind the end-cretaceous mass extinction

mammals outcompete dinosaurs

glaciation

volcanic activity

asteroid impact

Why is the theory “mammals outcompete dinosaurs” not accurate for the reason behind the end-cretaceous mass extinction

mammals existed before extinctions

mammals diversify after dinosaurs went extinct

doesn’t explain marine extinctions

Why is the theory “glaciation / climate cooling” not accurate for the reason behind the end-cretaceous mass extinction

dinosaurs are mobile and could leave cooling areas

extinction affected organisms globally, not just areas that cooled

Why is the theory “volcano eruptions” not accurate for the reason behind the end-cretaceous mass extinction

too small to explain sudden extinction peak

What is the main theory behind the end-cretaceous mass extinction

asteroid impact

What is the supporting evidence behind why the asteroids might have caused the end-cretaceous mass extinction

seeded plant survived (can go dormant in the dark)

crater matches size and age of event

global extinction pattern: must have been something large

What happened during “Time 0” after the asteroid

instant firestorms

ejected materials re-entering atmosphere

mega-tsunamis over a km tall near crash site

massive earthquakes

What happened during the “minutes/days later” after the asteroid

dust/soot/aerosols block sunlight

photosynthesis halts

rapid global cooling

What happened during the “weeks/years” after the asteroid

food web collapse

plankton crash led to marine die-off

herbivores starve, carnivores crash

fungi and detrivores thrive

ferns = pioneer species

What are three examples of what could cause a mass extinction

competition

predation

disease

How could competitions cause a mass extinction

invasive species

early mammals

What is an example of a disease that caused an extinction of elm trees

Dutch Elm Disease

What caused the dutch elm disease

fungal pathogen

What spread the dutch elm disease

beetles

What countries were impacted by the dutch elm diseae

North America

Europe

What are some examples of cataclysms that could cause an extinction

asteroids

volcanic eruptions

floods

ocean anoxia

What was the major extinction event in North America

Terminal Pleistocene Extinction

How many large animals became extinct after the terminal Pleistocene extinction

65-70%

How long ago did the Terminal Pleistocene Extinction occur

50,000 - 10,000 ya

What did the terminal Pleistocene extinction primarily affect

larger megafauna (>100 lb)

What are some examples of the larger megafauna that the Terminal Pleistocene Extinction affected

mammoth

mastodon

saber tooth cats

giant ground sloths

giant birds

horses and camels

dire wolves

Where did the Terminal Pleistocene Extinction begin

NW Alaska and continued SE

What was the main cause of the Terminal Pleistocene Extinction

human hunting pressure

What was the most recent large scale extinction

Terminal Pleistocene Extinction

How did we end up with a singular marsupial species in North America

The Great American Interchange

How long ago did the Great American Interchange occur

3.5 mya

How long ago was South America isolated before the Great American Interchange

80 mya

80 mya South America was dominated by

marsupials, flightless birds, herbivores

What happened when the landbridge between North and South America formed

bi-directional movement of animals

When the land bridge formed, carnivores moved _______

south

When the land bridge formed, marsupials and relatives moved _______

north

Which species was more successful in moving during the land bridge

North America species moving south

Why were the North American species that moved south more successful?

More efficient predators

Climate mismatch moving north

What was the most successful marsupial that migrated north

possum

What is the background extinction rate?

1 species per million species/year

What are the modern day rates?

100-1000X higher

What would be the sixth mass extinction

Modern Day Extinction

_____ of amphibians are threatened because of the Modern Day Extinction Threats

41%

_____ of mammals are threatened because of the Modern Day Extinction Threats

26%

_____ of birds are threatened because of the Modern Day Extinction Threats

13%

What type of species are the most vulnerable because of the threat of the Modern Day Extinction

Island Species

Why are island species threatened by the possibility of a modern day extinction

small populations

evolved with predators

What type of species are the least vulnerable because of the threat of the Modern Day Extinction

Large-bodied animals

Why are large bodied animals not threatened by the possibility of a modern day extinction

require large range

slow reproduction

What could be some causes of modern extinction

habitat loss

invasive species

overexploitation

pollution

climate change

disease

What are some examples of why habitat loss could lead to modern extinction

deforestation (Amazon), urban sprawl, wetland drainage

What are some examples of why invasive species could lead to modern extinction

cats in Hawaii, rats on islands, cane toads in Australia

What are some examples of why overexploitation could lead to modern extinction

overfishing (bluefin tuna), hunting (elephants, rhinos)

What are some examples of why pollution could lead to modern extinction

plastics in oceans, pesticides, heavy metals